Understanding Beef Quality Development and Different Feeding Regimes Jordan Christie Wicks ABSTRACT Consumption of beef is expected to increase as the world approaches nearly 9 billion inhabitants by the year 2050, adding unprecedented challenges to the future beef industry. Even so, maintaining quality will still be of utmost importance for producers for two reasons. First, the majority of US cattle are sold on the "grid", which offers both premiums and financial penalties based on quality grades. Second, consumers demand quality. Herein, we explored alternative, cost-saving feeding strategies that impact muscle biochemistry and ultimate meat quality in an effort to determine the most feasible management responses during times of sporadic markets. Our results show that reducing feed inputs from intensive feeding (grain-finished) regimes to maintenance diets of forage or grain up to 60 d had minimal effect on metabolic properties of muscle, thus preserving both quality and yield grades. Specifically, muscle metabolism remained largely unchanged, as indicated by lack of significance in oxidative and glycolytic proteins such as succinate dehydrogenase (SDH), citrate synthase (CS), lactate dehydrogenase (LDH), and phosphofructokinase-1 (PFK-1). Additionally, because maintenance rations were fed, we found no difference in non-esterified fatty acid (NEFA) concentration, or O-linked- β-N-acetylglucosamine (O-GlcNAc) protein abundance suggesting a longer or more aggressive feeding approach may be required to evoke such nutrient based muscle and quality differences. Because quality is important and is a factor for optimal pricing at market, intensive feeding practices are often needed to meet such standards. Still, as the cost of feeding increases, producers struggle to balance quality and profitability. To that end, we evaluated carcass quality of cattle subjected to a reduction of time on feed by 30 d, and found quality, yield and color were similar to that of cattle intensively fed for 120 days. Although, little differences were noted between indicators of postmortem metabolism, short-fed (SF) cattle showed a trend for greater adenosine monophosphate deaminase 1 (AMPD1), and significant difference in the expression of myosin heavy chain isoform (MyHC) IIX suggesting muscle of SF cattle is transiting away from that of grass-fed (CON) cattle. Even so, SF cattle proved to have similar color and quality to cattle fed for 120 days, or more traditionally fed. While we failed to detect differences in muscle between days on feed compared to that of CON (grass-fed), we observed differences in quality and yield between long fed and grass-fed cattle. These data suggest variances in quality may be a result of underlying mechanisms yet to be explained. Therefore, we explored the hallmark biomarkers credited for beef quality development. Despite significant differences in quality and yield grades, data resulted in no differences in myoglobin, oxidative or glycolytic proteins, or calpain-1 and calpastatin between varying phases of growth. However, based on our complementary transcriptomics data, we found linear trends in gene expression related to adipogenesis and muscle hypertrophy, implying these differences may simply be a result of growth rather than muscle function. When taken together, our data suggests severe nutrient restrictions may be required to evoke such a shift in muscle that leads to exacerbated differences in quality. A greater understanding of those mechanisms that drive meat quality development from a conventional grain feeding perspective may prove impactful for the future of our industry. / Doctor of Philosophy / As the demand for beef continues to increase, so does the demand for quality. Generally, consumers prefer beef that is bright-cherry red, possess adequate marbling, and offers a tender bite when consumed. These quality attributes are influenced by many factors, however plane of nutrition, or more simply nutrient energy source (grass vs grain) have shown to play a rather impactful role in quality development. Therefore, high-energy intensive feeding systems (feedlot) have been widely adopted by the US beef industry as a means of producing beef. Even so, the cost of gain for cattle is steadily increasing making profitability challenging from a producer standpoint. Therefore, the aim of this dissertation was to investigate low-input feeding strategies and the influence they have on beef quality. First, we tested nutrient availability's effect on muscle plasticity of mature market ready steers. Our results show that reducing feed inputs from intensive feeding (grain-finished) regimes to maintenance diets of forage or grain up to 60 d had minimal effect on metabolic properties of muscle, thus preserving both quality and yield grades. Next, we challenged varying degrees and plane of nutrition on finishing steers to better understand the extent to which intensive feeding has on ultimate beef quality. To that end, we evaluated carcass quality of cattle subjected to a reduction of time on feed by 30 d, and found quality, yield and color were similar to that of cattle intensively fed for 120 days. Although, little differences were noted between hallmark indicators of muscle fiber type, Short-fed (90 d) cattle proved to be transiting away from that of grass-fed (CON) cattle, aligning closer to consumer expectations of quality. Taken together, our data suggest variances in quality may be a result of underlying mechanisms yet to be explained. Therefore, we explored the hallmark biomarkers credited for beef quality development. Despite significant differences in quality and yield grades, data resulted in no differences in myoglobin, oxidative or glycolytic proteins, or calpain-1 and calpastatin between varying phases of growth. However, based on our complementary transcriptomics data, we found linear trends in gene expression related to adipogenesis and muscle hypertrophy, implying these differences may simply be a result of growth rather than muscle function. In conclusion, our data suggests severe nutrient restrictions may be required to evoke such a shift in muscle that leads to exacerbated differences in quality. A greater understanding of those mechanisms that drive meat quality development from a conventional grain feeding perspective may prove impactful for the future of our industry.

No description available.

The Hydrodyne process was used to tenderize early de-boned broiler (EB) breasts. The first objective was to determine effects of explosive and distance of the explosive to the meat surface. EB breasts were removed immediately after initial chill (45 min post-mortem), stored for 24 hours, and subjected to one of four treatment combinations. Hydrodyne treatment of 350 g at 20 cm produced the greatest increase in Warner-Bratzler shear (1.9-cm wide strips) tenderness (28.3%), and was the only treatment to increase tenderness (peak force 4.3 kg) to a level equivalent (P>0.05) to aged controls (CA; peak force 3.1 kg). The second objective was to determine quality (tenderness, purge loss, cooking loss, and color) and sensory characteristics of Hydrodyne treated (HYD) broiler breasts. Initial pH values for CA (5.86) and EB (5.71) breasts were different (P<0.05). Warner-Bratzler and Lee-Kramer shear values (1.0-cm wide and thick strips) for CA (1.56 kg; 6.0 kg*mm/g, respectively) were different from HYD (3.7 kg; 11.0 kg*mm/g, respectively) and EB breasts (4.7 kg; 12.1 kg*mm/g, respectively). CA resulted in more tender, flavorful, and juicer breasts than HYD and EB. HYD was lower in initial moisture release than EB. EB breasts with significant tenderness problems can be tenderized by the Hydrodyne process based on instrumental shear results. However, higher levels of explosive may be required to optimize tenderness improvement of breasts that vary significantly in initial tenderness. Incorporation of this technology, once optimized, on an industry production level would benefit poultry processors in reducing or eliminating broiler breast aging. / Master of Science

USDA Select bovine Biceps femoris (BF) samples were divided into four sections and randomly assigned to three hydrodynamic shock wave (HSW) treatments and a control. Different amounts of explosive (105 g, H1; 200 g, H2; 305 g, H3) were suspended in the center of the hemishell tank, 26.7 cm above the vacuum packaged beef placed on the bottom center of that water-filled tank and detonated, representing three HSW treatments. In addition, BF steaks (2.54-cm thick) from a different and limited common source (2 muscles) were packaged with each HSW designated BF section. These served as internal refernce steaks (IRS) for the six replications to determine if the HSW treatments physically altered the structural integrity of the meat. H1 and H3 decreased (P<0.05) Warner-Bratzler shear values of the IRS from 3.86 and 3.99 kg (controls) to 3.01 and 3.02 kg (HSW), respectively. H2 shear values, 3.86 (control) to 3.46 kg (HSW) were not different (P> 0.05). HSW and control BF sections were analyzed for protein solubility and then used to manufacture frankfurters formulated with 2.0% NaCl, 0.5 % sodium tripolyphosphate, 156 ppm sodium nitrite, 0.42 % sodium erythorbate, 2.0 % sucrose, and 25 % water. Frankfurters (cooked to 71 C) were evaluated for cooking yield, CIE L*a*b*, nitrosylhemochrome, Texture Profile Analysis (hardness, cohesiveness), and stress and strain (torsion testing). Compared to the control samples, the HSW did not affect (P>0.05) myofibrillar or sarcoplasmic protein solubility, cooking yield, or color. Textural properties and gel strength of the frankfurters were not affected (P>0.05) by the HSW. These results indicate that beef trim obtained from HSW processed meat can be used interchangeably with normal meat trim in the production of further processed meats since the functionality of meat protein is not affected significantly by the HSW process. / Master of Science

The purpose of this study was to determine the effects of tenderness on problem solving. Thirty-four female undergraduates participated. In the experimental condition, participants received instructions to reproduce a specific respiratory-posturo-facial pattern that had induced tenderness in previous studies. Participants in the control condition performed a non-emotional exercise. After either the pattern or the control exercise, participants completed one of two jigsaw puzzles. One puzzle had only an empty room while the other had a family scene. For participants who worked on the room puzzle, the tenderness pattern led to longer completion times. In contrast, for participants who worked on the family puzzle, the tenderness pattern led to shorter completion times.

Master of Science / Department of Animal Sciences and Industry / Michael E. Dikeman / The CVap steam generation oven was compared to a Blodgett forced-air, convection oven to examine effects of cooking method on yields, cooked color, tenderness, and sensory traits of beef Longissimus lumborum (LL), Deep pectoralis (DP), and Biceps femoris (BF) muscles cooked to three endpoint temperatures (65.6, 71.1, and 76.7°C). For each cooking treatment, four roasts were cooked in the CVap oven for a pre-determined, average amount of time, and two roasts were cooked in the Blodgett oven until they reached desired internal endpoint temperature. Cooking yields were higher (P ≤ 0.05) for BF and LL roasts cooked in the CVap. Slice shear force (SSF) for BF roasts cooked in the CVap were lower (P ≤ 0.05), whereas, SSF values for DP roasts cooked in the Blodgett were lower (P ≤ 0.05). No oven difference (P > 0.05) was found for LL roasts. Sensory tenderness scores for BF roasts cooked in the CVap were slightly higher (P ≤ 0.05) than roasts cooked in the Blodgett. Sensory scores for LL roasts cooked in the CVap were slightly higher but were also drier (both P ≤ 0.05). The CVap oven offers tenderization and cooking yield advantages for certain muscles.

Master of Science / Department of Animal Sciences and Industry / John A. Unruh / Forty-eight Brahman-cross male calves were fed to 26 mo of age and used to determine carcass cutability and meat quality characteristics of four muscles from intact bulls and steers castrated at 3, 7, or 12 mo of age grown under tropical pasture conditions. Longissimus lumborum (LL), Psoas major (PM), Gluteus medius (GM), and Semitendinosus (ST) steaks were aged for 2, 7, 14, or 28 d for Warner Bratzler shear force (WBSF) analysis. Live weight, carcass traits, and total subprimal yields were not affected by male sex condition. For PM, GM, and ST steaks, WBSF values were similar for steaks from intact bulls and steers castrated at all ages. For both PM and GM muscles, steaks aged for 28 d had the lowest (most tender) WBSF values and steaks aged for 2 d had the highest WBSF values. For the ST, WBSF values were highest for steaks aged 2 d. A treatment × aging interaction was detected for LL WBSF values. At 14 d of aging, LL steaks from steers castrated at 3 mo tended to have lower WBSF values than those from intact bulls. At 28 d of aging, steaks from steers had lower WBSF values than steaks from intact bulls and steaks from steers castrated at 3 mo tended to have lower WBSF values than steaks from steers castrated at 12 mo. For LL steaks from steers castrated at 3, 7 or12 mo, WBSF values linearly decreased with increased days of aging. Although all sensory panel data collected were not statistically different, LL steaks from steers castrated at 3 mo tended to have higher (more tender) scores for overall tenderness than steaks from intact bull. This study indicates that castration at 3 mo would be the recommended production practice as it provided the greatest improvement of LL tenderness over intact bulls with no differences in carcass traits or subprimal yields. The degree of improvement in tenderness due to aging is muscle dependent.

Considerando a importância da maciez dentre os atributos de qualidade de carnes, a necessidade do estabelecimento de um método mais rápido e moderno, que forneça resultados mais precisos, com baixa variabilidade e que possa ser utilizado para a determinação da maciez instrumental de diferentes cortes cárneos é uma demanda evidente. Sendo assim, o objetivo desta tese foi estudar a maciez instrumental de diferentes cortes cárneos bovinos, testando diferentes temperaturas finais de cocção e tempos de resfriamento no preparo das amostras e utilizando diferentes equipamentos, bem como estabelecer correlações entre a maciez instrumental e diversos outros atributos de qualidade de carnes. Foram avaliados os efeitos de três temperaturas finais de cocção (65, 70 e 75 °C) e dois tempos de resfriamento das amostras (4 e 24 horas) e ainda a utilização de três diferentes equipamentos (Texturômetro TAXT2icon equipado com lâminas de 1 e 3 mm de espessura e Warner-Bratzler clássico) na determinação da força de cisalhamento de cinco cortes cárneos bovinos. Os cortes foram caracterizados quanto aos atributos pH, índice de fragmentação miofibrilar, temperaturas de desnaturação das proteínas Actina e Miosina, cor instrumental, teor de colágeno, comprimento de sarcômeros, composição química e perda de peso por cocção. Foram determinadas as correlações lineares entre estes atributos, entre estes atributos e as forças de cisalhamento e entre as forças de cisalhamento. Foram estudados ainda, os comportamentos mecânico e estrutural dos cortes durante a realização dos testes de determinação da força de cisalhamento por meio da microestrutura das superfícies cisalhadas e das curvas mecânicas geradas durante os testes no texturômetro. Não houve efeito significativo do tempo de resfriamento nos resultados dos testes de determinação da força de cisalhamento. O Texturômetro com lâmina de 1 mm produziu valores mais baixos, enquanto que o Warner-Bratzler provocou os maiores valores. O Texturômetro com lâmina de 3 mm provocou menor precisão nos resultados. Em quase todos os casos, a temperatura de 65 °C produziu os menores valores de força de cisalhamento, enquanto que a utilização de 75 °C provocou os maiores valores. Foram observadas baixas correlações entre os atributos de qualidade avaliados e a força de cisalhamento dos cortes em estudo. Foram determinadas quatro equações de predição de força de cisalhamento de uma técnica com base nos resultados de outra. Os equipamentos e temperaturas finais de cocção utilizados ocasionaram diferentes comportamentos mecânicos e estruturais nos cortes cárneos avaliados. O Texturômetro com lâmina de 1 mm produziu menor variação nos resultados mas ao mesmo tempo, na maioria dos casos, provocou corte ao invés de cisalhamento nas amostras. Foi possível concluir que a utilização de diferentes equipamentos e pequenas variações na temperatura final de cocção das amostras pode ser uma grande fonte de variação nos resultados de testes de determinação da força de cisalhamento de carnes e que comparações entre resultados devem ser feitas com cautela observando estes detalhes. / Considering the importance of tenderness among the meat quality attributes, the need to establish a faster and more modern method that provides more accurate results with low variability and can be used to determine the instrumental tenderness of different meat cuts is an obvious demand. Thus, the objective of this thesis was to study the instrumental tenderness of different beef cuts, by testing different cooking endpoint temperatures and cooling times in the sample preparation step and using different equipment, as well as to establish correlations among the instrumental tenderness and several other meat quality attributes. The effects of using three cooking endpoint temperatures (65, 70 and 75 °C) and two cooling times of the samples (4 and 24 hours) and the use of three different equipment (TAXT2icon Texturometer equipped with shear blades of 1 and 3 mm thick, and a classical Warner-Bratzler) in the shear force determination of five beef cuts were evaluated. The cuts were evaluated for pH, myofibrillar fragmentation index, denaturation temperatures of Actin and Myosin proteins, instrumental color, collagen content, sarcomere length, chemical composition and cooking loss. Linear correlations between these attributes, between these attributes and shear force results and between shear force results were determined. The mechanical and structural behaviors of the cuts during the shear force tests were studied through the microstructure of the sheared surfaces and the mechanical curves generated during the tests in the texturometer. There was no significant effect of the cooling time on shear force results. The texturometer equipped with a 1 mm blade produced lower values, while Warner-Bratzler produced the higher ones. The texturometer equipped with a 3 mm blade resulted in decreased precision in the results. In most cases, the temperature of 65 °C produced the lowest shear force values, whereas the use of 75 °C resulted in the highest ones. Low correlations among the quality attributes evaluated and the shear force results of the cuts under study were observed. Four prediction equations of shear force were determined from one technique based on the results of another. The equipment and cooking endpoint temperatures used resulted in different mechanical and structural behaviors in the beef cuts evaluated. The texturometer equipped with a 1 mm blade produced less variation in the results, but at the same time, in most cases, it caused cutting rather than shearing of the samples. It is possible to conclude that the use of different equipment and small variations in the cooking endpoint temperature of the samples may be a great source of variation in the meat shear force results and that comparisons between results should be made with caution and observing these details.

abstract: The present research expands on prior research that demonstrated a prototypical facial expression in response to cute, baby-like Kindchenschema targets. This expression, referred to as the tenderness expression, is recognizable to onlookers as a response to such stimuli. Across two studies, the current research examined if there were differences in perceptions of trustworthiness (Studies 1 and 2) and willingness to trust (Study 2) toward individuals displaying the tenderness expression as compared to a Duchenne smile or a neutral expression. Results indicate the tenderness expression is associated with lower ratings of trustworthiness relative to a smile, but no differences among the expressions on willingness to trust. Exploratory analyses demonstrate a replicated pattern of differences on the Big Five Personality Inventory among these three expressions. While these findings were not consistent with a priori hypotheses, this research provides further insight into the social implications associated with this tenderness expression. / Dissertation/Thesis / Doctoral Dissertation Psychology 2019

Effects of three environments and their native or rye pasture forage systems on subsequent carcass characteristics, composition, and meat palatability were examined following grain feeding. Calves (F2 Angus x Bos indicus) with similar pre-weaning management and genetics were randomly assigned to one of eight treatments (McGregor-Calf; McGregor-Low; Uvalde-Low; Uvalde-High; Overton-Low, Rotational; Overton-Low, Continuous; Overton-High, Rotational; and Overton-High, Continuous). After approximately five months of grazing, cattle in forage groups were transported to McGregor and finished on a corn-milo ration to visually assessed 10 mm fat thickness. Longissimus muscle sections were randomly assigned into aging periods of 1, 7, 14, 21, 28, or 35 days and two-2.54 cm steaks were removed per section for Warner-Bratzler shear force and trained sensory analysis. After grazing, steers fed diets designed to produce higher rates of gain weighed more than steers at the same location fed diets designed for lower rates of gain. Within the high nutrition treatments, Uvalde-High steers had a lower average daily gain than steers in the Overton-High treatments. Differences in environment and nutritional treatments induced differences in rate of gain during the stocker phase. All forage treatment groups increased average daily gain in the feedlot phase. After the feedlot phase, steers varied in live weight due to treatment. Nutritional/environmental treatments affected ribeye area; kidney, pelvic and heart fat; and hot carcass weight, but not final yield grade. Treatment had minimal affects on quality grade characteristics. There was no affect by treatment on Warner-Bratzler shear force or sensory panel perception of myofibrillar tenderness, connective tissue amount, overall tenderness, or overall flavor intensity. Storage day affected shear force; steaks were toughest at 1 and 7 days of storage with shear force values decreasing after 7 days of storage. There was no interaction between environmental/nutritional treatment and storage day. Juiciness and cook loss were affected by treatment (P=0.0001). Overall, environment and nutrition had little impact on eating quality. Despite differences in average daily gain, it appears that steers may be fed forage diets followed by grain feeding to a similar fat thickness endpoint and produce steaks that are similar in palatability to grain-fed steers.